How do I combine LINQ expressions into one?

Question

I\'ve got a form with multiple fields on it (company name, postcode, etc.) which allows a user to search for companies in a database. If the user enters values in more than

Answer 1

EDIT: Jason's answer is now fuller than mine was in terms of the expression tree stuff, so I've removed that bit. However, I wanted to leave this:

I assume you're using these for a Where clause... why not just call Where with each expression in turn? That should have the same effect:

var query = ...;
foreach (var condition in conditions)
{
    query = query.Where(condition);
}